Department of Neuroscience, McKnight Brain Institute, Center for Alcohol Research, University of Florida College of Medicine, Gainesville, FL 32610, USA.
Alcohol Clin Exp Res. 2011 Jun;35(6):1122-33. doi: 10.1111/j.1530-0277.2011.01445.x. Epub 2011 Feb 17.
This study investigated ethanol influences on intracellular events that predispose developing neurons toward apoptosis and the capacity of the antioxidant α-tocopherol (vitamin E) and the neurotrophin brain-derived neurotrophic factor (BDNF) to modulate these effects. Assessments were made of the following: (i) ethanol-induced translocation of the pro-apoptotic Bax protein to the mitochondrial membrane, a key upstream event in the initiation of apoptotic cell death; (ii) disruption of the mitochondrial membrane potential (MMP) as a result of ethanol exposure, an important process in triggering the apoptotic cascade; and (iii) generation of damaging reactive oxygen species (ROS) as a function of ethanol exposure.
These interactions were investigated in cultured postnatal day 8 neonatal rat cerebellar granule cells, a population vulnerable to developmental ethanol exposure in vivo and in vitro. Bax mitochondrial translocation was analyzed via subcellular fractionation followed by Western blot, and mitochondrial membrane integrity was determined using the lipophilic dye, JC-1, that exhibits potential-dependent accumulation in the mitochondrial membrane as a function of the MMP.
Brief ethanol exposure in these preparations precipitated Bax translocation, but both vitamin E and BDNF reduced this effect to control levels. Ethanol treatment also resulted in a disturbance of the MMP, and this effect was blunted by the antioxidant and the neurotrophin. ROS generation was enhanced by a short ethanol exposure in these cells, but the production of these harmful free radicals was diminished to control levels by cotreatment with either vitamin E or BDNF.
These results indicate that both antioxidants and neurotrophic factors have the potential to ameliorate ethanol neurotoxicity and suggest possible interventions that could be implemented in preventing or lessening the severity of the damaging effects of ethanol in the developing central nervous system seen in the fetal alcohol syndrome (FAS).
本研究调查了乙醇对易导致发育中神经元凋亡的细胞内事件的影响，以及抗氧化剂 α-生育酚（维生素 E）和神经营养因子脑源性神经营养因子（BDNF）调节这些效应的能力。评估了以下方面：（i）乙醇诱导促凋亡 Bax 蛋白向线粒体膜的易位，这是凋亡细胞死亡起始的关键上游事件；（ii）乙醇暴露导致线粒体膜电位（MMP）的破坏，这是触发凋亡级联的重要过程；（iii）作为乙醇暴露的结果产生有害的活性氧物质（ROS）。
这些相互作用在培养的出生后 8 天的新生大鼠小脑颗粒细胞中进行了研究，这是一种在体内和体外易受发育性乙醇暴露影响的细胞群。通过亚细胞分级分离和 Western blot 分析 Bax 线粒体易位，并用亲脂性染料 JC-1 测定线粒体膜的完整性，该染料的潜在取决于 MMP，作为线粒体膜积聚的函数。
在这些制剂中短暂的乙醇暴露引发了 Bax 的易位，但维生素 E 和 BDNF 均可将这种作用降低至对照水平。乙醇处理还导致 MMP 紊乱，而这种作用被抗氧化剂和神经营养因子所减弱。在这些细胞中，短暂的乙醇暴露会增强 ROS 的产生，但用维生素 E 或 BDNF 共同处理会将这些有害自由基的产生降低至对照水平。
这些结果表明，抗氧化剂和神经营养因子都有可能减轻乙醇的神经毒性，并表明可能的干预措施，这些措施可用于预防或减轻胎儿酒精综合征（FAS）中发育中的中枢神经系统中乙醇的破坏性影响的严重程度。
